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  1. duke37

    wiring pid controller circuit

    You ask Is the output always at 1 level (full power) or should I expect increases in amps? The output will drop somewhat as the temperature rises since the resistance will rise with temperature. The variation will depend on the material of the wire, you can probably find this on the web or...
  2. duke37

    PWM motor control circuit-transistor issue

    Your Hoover motor may have been sufficiently thirsty to drop the voltage so that there is not enough voltage to fully turn on the fet (you need about 10V) explaining the high temperature. The average current of the motor will not rise as the speed is lowered, since the demanded power will be...
  3. duke37

    Building on Veroboard

    I have used the "dead bug" technique. Use some unetched printed circuit board or some tin plate and glue the integrated circuits onto it with their legs uppermost and connect other components in fresh air. If you need the odd land you can glue down a small square of printed circuit. This is a...
  4. duke37

    PWM motor control circuit-transistor issue

    The circuit looks OK to me. Do you know the current demand of your Hoover motor. Was this taking many amps. Try it directly on your 12V supply and measure the current. An interesting measurement would be to measure the average voltage at the output of the 555 using an analogue meter. It should...
  5. duke37

    wiring pid controller circuit

    To get a current of 10A you need a resistance of about 25 ohms. Measure the resistance of the element you have and then work out how much extra length you need. You must not have the extra element outside the furnace as it will get very hot and you will need to put it in an earthed box with a...
  6. duke37

    wiring pid controller circuit

    Stretching the coil will not add to the length of the wire so will not affect the resistance, I would not mess up your bricks by modifying the element. You have approx 230V in all parts of your estate, the difference between the on times could be due to the fact that you are probably going...
  7. duke37

    unknown LED Driver IC

    Is that a Zener diode or just an ordinary diode acting as a freewheel? It looks suspiciously like a voltage convertor to me, earthing the inductance to get sufficient current and then dumping it into the leds, Cunning.
  8. duke37

    wiring pid controller circuit

    What country are you in? What power voltages do you have? The power is determined by the resistance of the element and the voltage of the supply. If you have 110V and 230V, then run it on 110V which will give about a quarter of the power and half the current which the higher voltage will give...
  9. duke37

    PWM motor control circuit-transistor issue

    The IRFZ46N should be able to handle your current (about 1A) without breaking into a sweat! It needs to be turned fully on to minimise the heating. Does the gate get up to 10V when it is turned on? It needs to be turned on and off rapidly but the 555 should do that.
  10. duke37

    wiring pid controller circuit

    I have never worked with 110V which from your reply I assume you have. You will need some massive cables and they must not be overloaded. Do not change to a 40A breaker unless the cables are up to the job. You do not say how the furnace is constructed. If the heating element is laid in...
  11. duke37

    Circuit to surpress voltage ramp up

    Anything in parallel with the motor will use power and will not affect the motor speed unless you are mistreating the PSU with exessive overload. You could put a resistor in series with the motor and then by-pass it with a relay after a short time. You could put a FET in series wih the...
  12. duke37

    Dawn and dusk

    Possibly the easiest way would be to get a car window motor which raises the window and then has a limit switch to switch off the motor when it reaches the correct level. A relay from your light sensitive switch would replace the door switches. Get to know a tame recycler at your local scrap...
  13. duke37

    wiring pid controller circuit

    There could be two reasons for the power going off. 1. Too high a current. At 230V you will need 14A, at 110V abot 30A. 2. Leakage to earth due to insulation that has absorbed moisture since the furnace was last used. Check what had tripped the house system, whether it was an overcurrent...
  14. duke37

    Basic beginners mistake?

    You have Schmitt trigger, with feedback via the 270k resistor. This sets the deadband. To get a smaller deadband increase the resistor, try 1M, the deadband will reduce by a factor of about 4. The Schmitt trigger turns on and off rapidly and doesn't hunt at the control point.
  15. duke37

    i need step-down transformer

    You will need to give much more information so that you can be advised what can be obtained. Do you want a transformer or transistor?
  16. duke37

    Remote distance alert

    An alternative is to use sound which travels much slower than radio waves. You would need to produce a very short pulse which the other "watch" would send back. The time difference would indicate the separation distance. This is the principle of SONAR. Making a small waterpoof device would be...
  17. duke37

    Portable Electric Grill Shorting?

    24.4R is the resistance of the element and is correct. Your problem is the leakage between the element and ground. Measure the resistance between the earth pin and one of the element pins, it should be thousands of ohms.
  18. duke37

    gauge repair

    I have had a Google, the PN4356 is a general purpose transistor, 60V 500mA. EBC. I agree with Resqueline circuit
  19. duke37

    gauge repair

    I do not know what the PN4356 is but it lies between PN4304 and PN4391 which are n channel junction transistors, these could be connected to the sensors, they are likely to be delicate. More powerful transistors would be necessary to drive the bulbs. Are all eight the same number?
  20. duke37

    Basic beginners mistake?

    You are runnng from 12V so the voltage at the + input (pin 3) should be close to 6V, The voltage at - input (pin 2) depends on the temperature and will be about 6V at the switching temperature. Set your resistor to get 6V.
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